Black body background for imaging

Abstract

A light trap suitable for use in an optical imaging system includes a hollow sphere, with a hollow cylindrical tube attached substantially tangent to the surface of the sphere, and forming a chimney. The interior and exterior surfaces of the sphere are coated with a low-reflective coating, such as flat black paint. A sample to be imaged is placed over the opening of the chimney with an imaging system and illumination source directed downward into the chimney itself. Light which passes through or around the sample is captured in the sphere, so that it is not reflected back into the imaging system.

What is claimed is:  
     
       1. A light trap, comprising: 
       a hollow spheroidal enclosure;  
       a hollow elongate chimney which intersects with and forms an opening into an interior of said spheroidal enclosure, said opening being defined by an intersection of said chimney and said spheroidal enclosure; wherein  
       interior surfaces of the chimney and the sphere are coated with a light absorbing material; and  
       a longitudinal axis of said elongate chimney is eccentric to a center point of said spheroidal enclosure.  
     
     
       2. The light trap according to  claim 1 , wherein: 
       said spheroidal enclosure comprises a sphere; and  
       said chimney comprises a cylinder.  
     
     
       3. The light trap according to  claim 1 , wherein at said intersection, a longitudinal surface of said chimney is substantially tangent to said spheroidal enclosure. 
     
     
       4. The light trap according to  claim 2 , wherein at said intersection, a longitudinal surface of said chimney is substantially tangent to said spheroidal enclosure. 
     
     
       5. The light trap according to  claim 1 , wherein the opening formed by the intersection of the chimney has an area which is no greater than approximately 5 percent of total surface area of the enclosure. 
     
     
       6. The light trap according to  claim 1 , wherein the chimney has a lip in the form of a radially inwardly extending flange disposed at an external opening of the chimney. 
     
     
       7. A radiation trap, comprising: 
       a hollow spheroidal enclosure;  
       a hollow elongate chimney forming an opening in said spheroidal enclosure and positioned relative to the spheroidal enclosure such that radiation that passes through said chimney enters said spheroidal enclosure eccentric to a center of said spheroidal enclosure;  
       wherein an interior surface of the chimney and the interior surface of the spheroidal enclosure are coated with a light absorbent material.  
     
     
       8. The radiation trap according to  claim 7 , wherein said chimney is positioned relative to said spheroidal enclosure such that radiation which passes through said chimney enters said spheroidal enclosure approximately tangent to an interior surface thereof. 
     
     
       9. The radiation trap according to  claim 7 , wherein the opening formed by intersection of the chimney and the spheroidal enclosure has an area that is no greater than approximately 5 percent of total surface area of the enclosure. 
     
     
       10. The radiation trap according to  claim 8 , wherein the opening formed by the intersection of the cylindrical chimney has an area that is no greater than approximate 5 percent of total surface area of the enclosure. 
     
     
       11. The radiation trap according to  claim 7 , wherein at an intersection between said spheroidal enclosure and said chimney, a longitudinal surface of said cylindrical chimney is substantially tangent to said spheroidal enclosure. 
     
     
       12. The radiation trap according to  claim 8 , wherein at an intersection between said spheroidal enclosure and said chimney, a longitudinal surface of said cylindrical chimney is substantially tangent to said spheroidal enclosure. 
     
     
       13. An electromagnetic radiation trap, comprising: 
       a hollow elongate member having an opening for receiving light, and defining a light path along a longitudinal axis thereof;  
       a hollow spheroidal member connected to receive light traversing said light path through said elongate member; wherein  
       interior surfaces of said elongate member and of said spheroidal member are coated with a light absorbent material; and  
       said light path enters said spherical member in proximity to a tangent to the interior surface of the spheroidal member.  
     
     
       14. The electromagnetic radiation trap according to  claim 13 , wherein at said spheroidal member comprises a sphere, and said chimney comprises a cylinder.